28 | LEHIGH ALUMNI BULLETIN ilchrist, along with Kelly Schultz, associate professor of chemical and biological engineering, and Xuanhong Cheng, professor of bioengineering and materials science and engineering, received a $400,000, four-year grant in 2021 from the National Science Foundation (NSF) and the Center for the Advancement of Science in Space (CASIS), which is the manager of the International Space Station orbiting laboratory. The grant is to study “Thermophoresis in Non-Newtonian Fluids for Bioseparations.” Thermophoresis is a natural phenomenon in which a temperature gradient causes particles to migrate. It is used to separate molecules within a sample and could provide a way to detect the presence of disease in bodily fluids. But the problem is that temperature gradients cause a change in fluid density, and gravity takes over, causing the fluid to stir. The experiment detects the fluid flow, not the movement solely due to thermophoresis. Gravity, then, limits the detail of the data that can be extracted. Sending the experiment into space will leverage microgravity conditions to advance fundamental understanding of the movement of particles through liquids and gels, says Gilchrist. The understanding will help advance science in practical ways—such as helping to detect viral load. He explains: “Let’s say you go to a Japanese restaurant and get a bowl of miso soup. It’s mesmerizing. When it’s still hot, all the ingredients are swirling around. The liquid inside the bowl is hot, and because it’s hot, its density is lower, and the hot fluid rises and colder fluid near the surface falls, and recirculation ensues. But we want to study how the particles move due to the temperature gradient, not the fluid flow. “The only real way around that is to reduce the impact of gravity because the change in density doesn’t result in buoyancy in microgravity,” he says. “There’s no recirculation.” The space mission’s code name is TABOOS, which stands for Thermophoretic and Brownian Optical Observation System. Weather and circumstances permitting, the team’s “lab in a box” was scheduled to be launched in August from Northrop Grumman’s Mid-Atlantic Regional Spaceport on Wallops Island in Virginia. It will be part of the payload of the NG-19 Cygnus spacecraft aboard an Antares rocket. NASA contracts with Northrop Grumman and SpaceX for resupply missions. Gilchrist says the lab experiments are scheduled to be launched in mid-December on NG-20 and he plans to view that one in person. “I want to see it go up,” he says. Gilchrist says he started thinking about the research project in 2016 and teamed up with Schultz. At the time, their offices were next to each other in Iacocca Hall on the Mountaintop Campus. Their research spaces are now in the new Health, Science and Technology Building. “The scientific effort is 50-50 between Kelly and me. Her science and my science are the perfect match for getting more accurate measurements for thermophoresis than have ever been done before,” says Gilchrist. “My idea was, we would approach this idea of, how do particles behave in complex fluids, in temperature gradients. My area of expertise is particle technology and transport and how things move and flow. Kelly’s expertise is in complex fluids and how to perform particle tracking microrheology.” Gilchrist says they applied for Lehigh’s Collaborative Research Opportunity (CORE) grant and were initially denied. They applied again in 2018 and were successful, receiving a $60,000 grant from Lehigh’s Office of the Vice Provost for Research. The program is part of Lehigh’s strategy for “building a vital research portfolio that is responsive to the grand challenges of our society.” The NSF grant followed. The key, Gilchrist says, was showing how the research could be used to benefit mankind. Teaming up with Cheng, who develops novel microfluidic devices for point of care and global health diagnostics, was the game changer. Cheng invents devices that separate viruses in order to detect viral loads from biological fluids and natural samples. “This is From left, Professor Xuanhong Cheng, Ph.D. student Nazrin Hasanova '21 and Professor James Gilchrist
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